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Jim Baen’s Universe

Page 70

by Edited by Eric Flint


  Also con­si­der that sa­me ra­il­gun system as a pos­sib­le de­fen­se for as­te­ro­ids, me­te­ors, and co­mets that might be on an im­pact tra­j­ec­tory with Earth in the fu­tu­re. This co­uld be a ma­j­or re­ason for ha­ving a mi­li­tary ba­se on the mo­on. As it stands cur­rently, we ha­ve no li­ne of de­fen­se for such im­pacts.

  And then the­re is the ot­her big sci­en­ce fic­ti­on pos­si­bi­lity-mat­he­ma­ti­cal­ly it is a fi­ni­te pro­ba­bi­lity-that the Earth is in­va­ded by ali­ens. Ha­ving our mi­li­tary in mul­tip­le lo­ca­ti­ons might be use­ful in that si­tu­ati­on. Ha­ving hu­ma­nity spre­ad out in mul­tip­le pla­ces wo­uldn’t be a bad idea, eit­her.

  Well, one thing for cer­ta­in tho­ugh, mi­li­ta­ri­za­ti­on of the mo­on is a long way off. So, if you are one of tho­se types that is op­po­sed to such an idea, then don’t pa­nic. The­re is plenty of ci­vi­li­an ex­p­lo­ra­ti­on to be had on the mo­on. The­re is plenty of sci­en­ce to dis­co­ver and un­co­ver on the mo­on. Per­haps so­me smart en­t­rep­re­ne­ur will de­ve­lop an eco­no­mi­cal­ly vi­ab­le bu­si­ness mo­del for mo­on mis­si­ons. May­be the­re will be a Club Med Tran­qu­ility Ba­se in the not so dis­tant fu­tu­re.

  Whatever the out­co­me is, the thing to re­mem­ber is that the­re is a big bright fu­tu­re for spa­ce ex­p­lo­ra­ti­on that starts on the mo­on. And, if the­re are ide­as that you ha­ve for re­asons for go­ing and sta­ying on the mo­on, by all me­ans don’t ke­ep them to yo­ur­self. NA­SA is lo­oking for gre­at ide­as and ap­pli­ca­ti­ons for spa­ce tra­vel. What to do on­ce we get to the mo­on is such a qu­es­ti­on that Ad­mi­nis­t­ra­tor Grif­fin had the­se words to pass along in an E-ma­il to his up­per ec­he­lon ad­vi­sors:

  The next step out is the mo­on. We're go­ing to get, and pro­bably al­re­ady are get­ting, the sa­me cri­ti­cisms as for ISS. This is the "why go to the mo­on?" the­me.

  We've got the ar­c­hi­tec­tu­re in pla­ce and ge­ne­ral­ly ac­cep­ted. That's the "inter­s­ta­te hig­h­way" ana­logy I've ma­de. So now, we ne­ed to start tal­king abo­ut tho­se exit ramps I've re­fer­red to. What ARE we go­ing to do on the mo­on? To what end? And with whom? I ha­ve ide­as, of co­ur­se. (I AL­WAYS ha­ve ide­as; it's a gi­ven.) But my ide­as don't mat­ter. Now is the ti­me to start wor­king with our own sci­en­ce com­mu­nity and with the In­ter­na­ti­onals to de­fi­ne the prog­ram of lu­nar ac­ti­vity that ma­kes the most sen­se to the most pe­op­le. I ke­ep sa­ying-be­ca­use it's true-that it's not the trip that mat­ters, it's the des­ti­na­ti­on, and what we do the­re. We’ve got to get star­ted on this.

  … and the In­ter­na­ti­onal Par­t­ners to get star­ted down the track on pul­ling to­get­her an in­ter­na­ti­onal co­ali­ti­on. They are an­no­yed and im­pa­ti­ent with our de­lays sin­ce the Vi­si­on spe­ech. We ne­ed to be, and be se­en to be, pro­ac­ti­ve in se­eking the­ir in­vol­ve­ment. We ne­ed to work with them, not pres­c­ri­be to them, re­gar­ding what we can do to­get­her on the mo­on.

  Beyond the mo­on is Mars, ro­bots first. Most of the In­ter­na­ti­onals are at pre­sent mo­re in­te­res­ted in Mars, as I he­ar the gos­sip. Fi­ne, we can't tell them what to be in­te­res­ted in. But our ro­ad to Mars go­es thro­ugh the mo­on, and we sho­uld be ab­le to en­list them to jo­in on that path.

  Everyone… wants to be part of ma­king ex­p­lo­ra­ti­on what NA­SA do­es. It won't sur­vi­ve if all we worry abo­ut is get­ting the­re. That was the es­sen­ti­al first step. But it has to sell it­self on what it is that we DO the­re.

  So When are We Go­ing?

  As the prog­ram cur­rently stands, NA­SA plans to be tes­ting the systems for the CEV as early as this ye­ar. De­sign stu­di­es and re­vi­ews are to be­gin no la­ter than 2008. Su­bor­bi­tal flight tes­ting of the spa­cec­raft is to be­gin so­me­ti­me aro­und 2009 to 2010. The­re are at le­ast three so-cal­led “risk re­duc­ti­on flights” sche­du­led bet­we­en 2010 and 2012. The ho­pes are to ha­ve the CEV flights pro­ven and re­ady for ope­ra­ti­on by 2012. This will al­low de­com­mis­si­oning of the shut­tles as the CEV will be ab­le to tran­s­port crew­mem­bers to the ISS.

  The he­avy la­unch ve­hic­le, CLV, will be de­ve­lo­ped pa­ral­lel to the CEV. Ho­we­ver, the flight re­adi­ness of the CEV se­ems to ha­ve pri­ority sta­tus. The cur­rent NA­SA plan is to im­p­le­ment what Grif­fin re­fers to as the “Lu­nar So­oner” plan that will see flight tes­ting of the CLV so­me­ti­me bet­we­en 2013 to 2016 with flight re­adi­ness so­on af­ter. The “Lu­nar So­oner” plan op­ti­mis­ti­cal­ly has the CEV and CLV re­ady for the first man­ned Mo­on mis­si­on by March of 2017! That is only ele­ven ye­ars away and is three ye­ars ahe­ad of the ori­gi­nal sche­du­le sug­ges­ted by Pre­si­dent Bush. So just be pa­ti­ent, we are li­ab­le to ma­ke it back to the mo­on wit­hin the li­fe­ti­mes of the ma­j­ority of pe­op­le that are re­ading this ar­tic­le!

  ADD NO­TE:

  "Since this ar­tic­le was writ­ten NA­SA has so­li­di­fi­ed the CEV prog­ram mo­re and has cho­sen new des­c­rip­ti­ons for the la­unch ve­hic­le systems. The small cap­su­le that car­ri­es the crew will be the Crew Ex­p­lo­ra­ti­on Ve­hic­le or CEV. The mo­di­fi­ed so­lid roc­ket bo­os­ter and the li­qu­id fu­el up­per­s­ta­ge that lifts the CEV in­to or­bit is the Crew Ex­p­lo­ra­ti­on Ve­hic­le La­unch Ve­hic­le or CLV. The lar­ger system that lifts the LSAM and ot­her car­go in­to or­bit will be known as the Car­go La­unch Ve­hic­le or the CaLV."

  ****

  Columns

  Why Die?

  Jim Baen

  Note: The aut­hor wo­uld li­ke to ac­k­now­led­ge the ines­ti­mab­le help re­ce­ived from con­ver­sa­ti­ons with Dr Lam­b­s­he­ad, and for the en­t­hu­si­as­tic sup­port of Pro­fes­sor Eg­lund, who­se anal­y­sis fol­lows the ar­tic­le. The­re are pro­bably se­ve­ral per­sons on the pla­net who will un­der­s­tand the anal­y­sis.

  Many pe­op­le ha­ve sug­ges­ted that aging is a pre-prog­ram­med, ge­ne­ti­cal­ly con­t­rol­led fun­c­ti­on in hig­her ani­mals. This ap­pe­ars to be con­fir­med by the re­se­arch fin­dings of Cynthia Ken­yon, an emi­nently res­pec­tab­le sci­en­tist who pub­lis­hes in pe­er-re­vi­ewed jo­ur­nals, on aging in ne­ma­to­des. She re­por­ted ex­ten­si­ons of ne­ma­to­de li­fes­pan of fi­ve ti­mes nor­mal, i.e. from aro­und two we­eks to ten, with the­ir ap­pa­rent vi­go­ur un­di­mi­nis­hed un­til shortly be­fo­re de­ath. In ot­her words, they don’t just drag out old age but fun­c­ti­on pro­perly for an ex­ten­ded pe­ri­od.

  She ac­com­p­lis­hes this by se­lec­ti­vely bloc­king the ex­p­res­si­on of va­ri­o­us “DAF” ge­nes, in­c­lu­ding DAF-2 and DAF-16. DAF-2 sup­pres­ses the ac­ti­on of DAF-16, the lat­ter trig­gers or sup­pres­ses at le­ast six ot­her ge­nes the end re­sult of which is to pro­mo­te lon­ge­vity. DAF-16 se­ems to in­f­lu­en­ce the pro­duc­ti­on of pro­te­ins that pro­tect aga­inst free ra­di­cal da­ma­ge. So it co­uld be sa­id that DAF-2 has the fun­c­ti­on of de­li­be­ra­tely li­mi­ting a ne­ma­to­de’s li­fe span.

  Of co­ur­se, one has to be ca­re­ful ex­t­ra­po­la­ting from a ne­ma­to­de worm with a li­fes­pan me­asu­red in we­eks to so­met­hing long li­ved li­ke a hu­man be­ing. In ne­ma­to­des, DAF-2 and DAF-16 are as­so­ci­ated with mo­ul­ting. Ne­ma­to­des are Ec­d­y­so­zo­ans (mo­ul­ting ani­mals) and the­se ha­ve the abi­lity to go in­to a spe­ci­al ‘shut down’ sta­te, known as ‘da­u­er lar­vae’ in the ca­se of the Ken­yon’s test ani­mal, the ne­ma­to­de Ca­enor­hab­di­tis ele­gans.

  Human be­ings ne­it­her mo­ult nor go in­to a shut down mo­de (not even te­ena­gers). Ho­we­ver, the DAF-2 ge­ne is si­mi­lar to a ge­ne in mam­mals cal­led IGF-1 that is con�
�nec­ted with in­su­lin fun­c­ti­on. Mar­tin Hol­zen­ber­ger cre­ated stra­ins of mi­ce in which one or both co­pi­es of the ro­dent ge­ne for the IGF-1 re­cep­tor had mu­ta­ti­ons. Mi­ce lac­king any nor­mal co­pi­es di­ed as em­b­r­yos. Ho­we­ver, mi­ce with one wor­king copy de­ve­lo­ped nor­mal­ly and li­ved, on ave­ra­ge, 26 per­cent lon­ger than did ani­mals with two nor­mal co­pi­es of the IGF-1 re­cep­tor ge­ne.

  For the pur­po­ses of this ar­tic­le, let us as­su­me that get­ting old and dying is a de­fi­ned pro­cess, a pro­cess that is con­t­rol­led by our ge­nes; that our li­fe span is de­li­be­ra­tely li­mi­ted. Why? This se­ems as­to­nis­hingly co­un­ter-evo­lu­ti­onary. The two ba­sic dri­ving for­ces in evo­lu­ti­on are (i) sur­vi­val and (ii) suc­cess in ma­ting (for se­xu­al or­ga­nisms). Sur­vi­ving by de­fi­ni­ti­on im­p­li­es ex­ten­si­on of li­fe span. Ho­we­ver, it is al­so true that for many or­ga­nisms that the lon­ger an or­ga­nism sur­vi­ves the mo­re suc­ces­sful it will be at ma­ting - even ge­eks will ma­na­ge to rep­ro­du­ce if gi­ven eno­ugh chan­ces.

  So if our li­fe span is de­li­be­ra­tely li­mi­ted by our ge­nes then the­re must be so­me evo­lu­ti­onary ad­van­ta­ge. The rest of this ar­tic­le will try and ad­dress this po­int.

  One pos­si­bi­lity is that we li­mit our li­fes­pan by the ne­ed for op­ti­mal per­for­man­ce up to the ti­me of suc­ces­sful rep­ro­duc­ti­on. This is the ra­cing car ana­logy. An en­gi­ne­er de­sig­ning a Ford or a Pe­uge­ot tends to over-en­gi­ne­er to gi­ve re­li­abi­lity and a de­cent li­fes­pan rat­her than op­ti­mi­se for per­for­man­ce. In con­t­rast, the ra­cing ge­ni­us Co­lin Chap­man used to exa­mi­ne his cars af­ter a ra­ce and any com­po­nent that was in too go­od a con­di­ti­on was promptly lig­h­te­ned. An ide­al Chap­man ra­cing car wo­uld fall to pi­eces one inch af­ter cros­sing the fi­nish li­ne - but in first pla­ce!

  The ra­cing car ana­logy do­es not re­al­ly se­em to ex­p­la­in Ken­yon’s re­sults be­ca­use when DAF-2 is sup­pres­sed the worms stay yo­un­ger lon­ger; they do not stag­ger on in se­ni­lity. It is al­most as if the ge­nes do not ca­re how long a worm co­uld li­ve or what con­di­ti­on it might be in thro­ugh most of that li­fe but just de­ci­de it has li­ved long eno­ugh. What evo­lu­ti­onary mec­ha­nism co­uld ca­use this?

  In Utah, stu­di­es ha­ve be­en do­ne that show that it is pos­sib­le, in fact sur­p­ri­singly easy, to track the pre­sen­ce of pol­y­ga­mo­us mar­ri­ages by the oc­cur­ren­ce of ba­bi­es with birth de­fects. It turns out that ha­ving a few highly pro­li­fic ma­les ma­kes a sur­p­ri­singly lar­ge im­pact on the oc­cur­ren­ce of do­ub­le re­ces­si­ves in the ge­ne­ral po­pu­la­ti­on, and that this in turn le­ads to a sur­p­ri­singly lar­ge num­ber of bir­th-de­fects, chil­d­ren with Down’s Syndro­me, cleft pa­la­te, club fe­et, va­ri­o­us le­ukod­y­s­t­rop­hi­es and the li­ke oc­cur much mo­re com­monly than they wo­uld wit­ho­ut the pri­or pre­sen­ce of the­se ma­les. This ob­ser­va­ti­on is anec­do­tal­ly com­mon hu­man ex­pe­ri­en­ce. In­b­re­eding ca­uses an in­c­re­ase in nasty re­ces­si­ve ge­nes in the po­pu­la­ti­on and pol­y­gamy ine­vi­tably will in­c­re­ase in­b­re­eding.

  This is a com­mon prob­lem in con­ser­va­ti­on. On­ce a po­pu­la­ti­on of an or­ga­nism drops be­low a cer­ta­in le­vel then the spe­ci­es is in ter­rib­le tro­ub­le. In the­ory, one co­uld rec­re­ate a spe­ci­es from a sin­g­le ma­le and fe­ma­le. In prac­ti­ce, the­re are li­kely to be enor­mo­us ge­ne­tic is­su­es.

  For hu­man po­pu­la­ti­ons, in­b­re­eding is li­kely to be es­pe­ci­al­ly dan­ge­ro­us for two re­asons. The first is that the hu­man ge­no­me is par­ti­cu­larly messy com­pa­red to ot­her mam­mals such as dogs or rats. The se­cond re­ason is that rep­ro­duc­ti­ve suc­cess of ma­les in hu­man be­ings (who are highly so­ci­al ani­mals) tends to be cor­re­la­ted with sta­tus and sta­tus tends to in­c­re­ase with age. As the hypot­he­ti­cal TV in­ter­vi­ewer put to the yo­ung blon­de, ‘What first at­trac­ted you to this el­derly, bal­ding, mul­ti­mil­li­ona­ire Miss Smith?’ The we­althy mid­dle-aged man with a yo­un­ger trophy wi­fe is a phe­no­me­non ob­ser­ved in all hu­man so­ci­ety. A long li­fe span in men is mo­re of an is­sue be­ca­use one high sta­tus man can im­p­reg­na­te many wo­men. Re­ason one will tend to ac­cen­tu­ate the im­pact of re­ason two.

  So if a me­ta-po­pu­la­ti­on (a sub­g­ro­up) of a spe­ci­es that has mu­ta­ti­ons that shor­ten its li­fes­pan has of­f­s­p­ring that are mo­re suc­ces­sful than the of­f­s­p­ring of a lon­ger-li­ved me­ta-po­pu­la­ti­on then the for­mer po­pu­la­ti­on will rep­la­ce the lat­ter. An evo­lu­ti­onary mec­ha­nism, the­re­fo­re, exists that co­uld pro­mo­te de­ath ge­nes.

  Just be­ca­use this is lo­gi­cal and re­aso­nab­le do­es not ma­ke it true, but I le­ave you with one fi­nal tho­ught. Wo­men com­monly li­ve lon­ger than men and, in my mo­del, it is long li­ved men that sho­uld be mo­re dan­ge­ro­us to the spe­ci­es. If you are ma­le, then na­tu­re co­uld ha­ve it in for you.

  A genetic model for eternal life as an evolutionary strategy

  Karl In­ne Ug­land

  University of Os­lo,

  Marine Zo­ology

  Pb 1066, 0316 Os­lo, Nor­way.

  (Portions of the equ­ati­ons of this pa­per are for­mat­ted as grap­hics which will not ren­der in this for­mat. Ple­ase vi­ew this pa­per at the on-li­ne html ver­si­on or in the PDF’s for cor­rectly for­mat­ted equ­ati­ons.)

  Introduction

  Classical and mo­le­cu­lar ge­ne­tics are con­cer­ned with the na­tu­re and tran­s­mis­si­on of ge­ne­tic in­for­ma­ti­on, and how this in­for­ma­ti­on is tran­s­la­ted in­to phe­not­y­pes. Po­pu­la­ti­on ge­ne­tics the­ory is most suc­ces­sful when de­aling with simply in­he­ri­ted tra­its - tra­its who­se tran­s­mis­si­on fol­lows sim­p­le Men­de­li­an ru­les. Yet many of the most in­te­res­ting and im­por­tant tra­its are not so simply in­he­ri­ted: they de­pend on se­ve­ral ge­nes, which of­ten in­te­ract in com­p­lex ways with one anot­her and with the en­vi­ron­ment.

  Population ge­ne­tics in­c­lu­des a lar­ge body of mat­he­ma­ti­cal the­ory; one of the most ric­hest and most suc­ces­sful bo­di­es of mat­he­ma­tics in bi­ology. The use­ful ap­pli­ca­ti­on of this the­ory has be­en gre­atly en­han­ced in re­cent ye­ars by new mo­le­cu­lar tec­h­ni­qu­es.

  Usually, the first step is to study the fre­qu­ency of dif­fe­rent ge­not­y­pes or phe­not­y­pes in a sam­p­le of the po­pu­la­ti­on. The con­cept lo­cus is used to de­sig­na­te a chro­mo­so­mal lo­ca­ti­on, and the con­cept al­le­le de­sig­na­tes an al­ter­na­ti­ve form of the ge­ne oc­cup­ying the con­si­de­red po­si­ti­on. Usu­al­ly we are mo­re in­te­res­ted in the fre­qu­en­ci­es of the dif­fe­rent al­le­les than in the fre­qu­en­ci­es of the dif­fe­rent ge­not­y­pes. This is be­ca­use al­le­le fre­qu­ency is a mo­re eco­no­mi­cal way to cha­rac­te­ri­se the po­pu­la­ti­on. The num­ber of pos­sib­le ge­not­y­pes is enor­mo­us. Con­si­der for exam­p­le 100 lo­ci, each with 4 seg­re­ga­ting al­le­les. With 4 al­le­les A, B, C, D the to­tal num­ber of pos­sib­le ge­not­y­pes at each lo­cus is 10: (1) fo­ur ho­moz­y­go­tes: AA, BB, CC and DD plus (2) six he­te­roz­y­go­tes: AB, AC, AD, BC, BD and CD. For all 100 lo­ci the­re are thus 10100 pos­sib­le ge­not­y­pes, i.e. mo­re than the num­ber of atoms in our uni­ver­se! It is, the­re­fo­re, much bet­ter to stick to al­le­le-fre­qu­en­ci­es.

  The cha­rac­te­ri­sa­ti­on of a po­pu­la­ti­on in terms of al­le­le fre­qu­en­ci­es rat­her than ge­not­y­pe fre­qu­en­ci­es has anot­her ad­van­ta­ge. In a Men­de­li­an po­pu­la­ti
­on, the ge­not­y­pes are scram­b­led every ge­ne­ra­ti­on by seg­re­ga­ti­on and re­com­bi­na­ti­on. New com­bi­na­ti­ons are put to­get­her only to be ta­ken apart in la­ter ge­ne­ra­ti­ons. If we are to study a po­pu­la­ti­on over a ti­me pe­ri­od of mo­re than a few ge­ne­ra­ti­ons, then the stab­le en­tity is the ge­ne.

  In na­tu­re it is the or­ga­nism that sur­vi­ves and rep­ro­du­ces, so na­tu­ral se­lec­ti­on acts on the or­ga­nisms and it is the fit­ness of the or­ga­nism that de­ter­mi­nes the li­ke­li­ho­od of sur­vi­val and rep­ro­duc­ti­on. But what an in­di­vi­du­al ac­tu­al­ly tran­s­mits to fu­tu­re ge­ne­ra­ti­ons is a ran­dom sam­p­le of its ge­nes, and tho­se ge­nes that in­c­re­ase fit­ness will be mo­re rep­re­sen­ted in fu­tu­re ge­ne­ra­ti­ons. Thus, the­re is se­lec­ti­on of ge­nes de­ter­mi­ning the pro­per­ti­es li­ke vi­go­ur and fer­ti­lity.

  Any des­c­rip­ti­on of na­tu­re, whet­her ver­bal or mat­he­ma­ti­cal, will only be a ca­ri­ca­tu­re and the­re­fo­re ne­ces­sa­rily in­com­p­le­te. In the pre­vi­o­us cen­tury, sci­en­tists re­ali­sed that we can­not ask whet­her a mat­he­ma­ti­cal mo­del is true, we can only ask if it gi­ves a go­od or bad des­c­rip­ti­on of our da­ta, and so may be used for pre­dic­ti­on of fu­tu­re ob­ser­va­ti­ons and ex­pe­ri­ments. So­me mo­dels are only ro­ugh ca­ri­ca­tu­res, but the ad­van­ta­ge with this class of mo­dels is that they are easy to un­der­s­tand. An exam­p­le is the suc­ces­sful the­ory of ther­mod­y­na­mics whe­re the gas mo­le­cu­les are re­gar­ded as elas­tic sphe­res.

 

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